The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Turbocharged engines commonly include an exhaust driven turbocharger that increases engine output by increasing airflow to the cylinders. As a result, turbocharged engines provide increased horsepower over equivalently sized naturally aspirated engines.
One turbocharger design includes a variable nozzle turbocharger (VNT). VNT's include variable position vanes that regulate the amount of air delivered through the VNT. The vane position ranges from a fully-open position to a fully-closed position. In the fully-closed position, the VNT delivers a maximum amount of airflow to the engine. In the fully-open position, the VNT delivers a minimum amount of airflow to the engine. The vanes can be positioned between the fully-open and fully-closed positions to provide an intermediate amount of airflow to the engine. A vane actuator adjusts the vane position based on a control signal and a vane position sensor generates a signal indicating the actual vane position for feedback control.
During high temperature conditions and/or high back pressure conditions, movement of the vanes can be inhibited. Such conditions can negatively impact the performance of the turbocharger and the overall performance of the engine system.